1. Field of the Invention
The present invention relates to an individual inter-blade platform for a bladed disc of a turbomachine rotor, especially the rotor of the fan of a turbojet engine or the rotor of a compression stage of an aircraft engine.
2. Summary of the Prior Art
In the construction of turbomachine rotors, particularly rotors of the type mentioned above, it is known, for example for the purpose of permitting unitary demounting in the case of large chord blades having a substantial twist and/or facilitating their manufacture, either in the course of machining operations or if using composite materials, to construct the blades in several parts, and in particular by providing separate inter-blade platforms, one of the functions of which is to form a continuous wall for bounding the air flow path. Examples of these known techniques are described in GB-A-2 006 883, GB-A-2 171 151 and U.S. Pat. No. 3,393,862 which disclose the use of separate inter-blade platforms and various ways of securing them on the rotor. The use of composite materials in the construction of these parts has also been envisaged.
FR-A-2639402 discloses another example of the construction with particular methods of effecting the fixing of the platform on the rotor disc, and in some cases the platform is made from a composite material of laminated type by winding or laying of fabrics. Another example of the construction is disclosed in FR-A-2 679 296 which describes a platform formed by two parts made of composite material, namely a four-sided structural frame of trapezoidal section and made of laminated material, and a plate made of polyurethane type material.
It is an object of the invention to provide an inter-blade platform for a rotor which retains the above-mentioned advantages of existing solutions, particularly the ability to demount the rotor blades individually, and which has a mass which is as small as possible, this being an important requirement for a rotating part, especially in aeronautical applications.
A further object of the invention is to provide a platform with sufficient rigidity such that it does not flex, particularly under the action of a centrifugal field, and thus does not alter local aerodynamic conditions.
Furthermore, having regard to the applications envisaged, and particularly in the case of a fan which is placed at the upstream end of the engine, it is necessary for the platform to exhibit suitable resistance to impact and erosion resulting from the ingestion of foreign bodies at the engine intake, such as hailstones, grit, sand and various types of dust.